Restek

Restek at NACRW 2024

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14-17 July, Fort Lauderdale, FL, U.S.

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VENDOR SEMINAR

 

Recent Developments in Emerging and Persistent Contaminants

Monday, July 15, 7:15-8:15 a.m.
Colton Myers (presenter), Melinda Urich, Alexis Shelow
Restek Corporation

Abstract
PFAS, mycotoxins, pesticides, and many other compound classes continue to disrupt laboratory workflows due to their chemical nature and the difficult matrices that they persist in. High-throughput laboratories need clean and effective solutions to navigate these challenges as methods continue to emerge targeting lower limits of detection. Improving areas, such as background contamination, analyte behavior, and instrument uptime, is critical for accurate quantitation and creating a safer world. These challenges can be mitigated through novel sample preparation and chromatographic products. New advancements from the Restek laboratories will be presented that showcase innovative LC, GC, and sample preparation solutions that target these emerging compound classes and problematic matrices.

 

ORAL PRESENTATIONS

 

Exploration of New Low-Pressure GC columns for Food and Environment Emerging Contaminants

Monday, July 15, 1:50–2:10 p.m.
Jana Hepner, (presenter), Whitney Dudek-Salisbury, Chris English
Restek Corporation

Abstract
The Low-Pressure GC (LPGC technique) has been successfully used in the past for pesticide residues’ analysis. However, the technique is very versatile, and it allows for other applications, especially if different column phases are used. So far, the majority of the applications have been using the “5”-type phase (95% dimethylpolysiloxane,5% diphenyl polymer). To expand on the previous applications, four additional column phases were selected(cyanopropylphenyl dimethylpolysiloxane; 50% dimethylsiloxane, 50% diphenyl; 65% dimethylsiloxane, 35%diphenyl; and trifluoropropylmethyl polysiloxane phases) to analyze various food and environmental contaminants, such as nitrosamines, alkylfurans, phthalates, arylamines and fluorotelomer alcohols. The LPGC techniques provided significant reduction in run times (up to 3.3x faster runs) and helium consumption reduction(up to 81% less helium used), while keeping an acceptable resolution.

 

Reduced Instrument Downtime for Organochlorine Pesticide Analysis by Using an Optimized SPE Cartridge for Sample Extract Cleanup

Wednesday, July 17, 8:55–9:15 a.m.
Alexis Shelow (presenter), Jason Thomas
Restek Corporation

Abstract
Some of the most commonly encountered problems experienced by those analyzing environmental samples for organochlorine pesticides are instrument downtime and shortened calibration periods both due to the deleterious effects of coextracted matrix components that are introduced into the analytical instrument during sample injection. In addition to this, chromatographic interferences complicating identification and quantification have also made life difficult for environmental analysts. Although there are cleanup options provided such as Florisil, silica gel, and alumina, these normal phase solutions often do not adequately remove the less polar and high molecular weight compounds that are responsible for diminishing instrumental performance and sample path inertness.

In this presentation, a cartridge is introduced that is designed specifically to be utilized exactly like the frequently employed Florisil cartridge, but to a much superior effect for highly pigmented and inlet degrading samples. What this means for the analyst is the ability to consistently generate calibration curves that can be maintained longer and reduced instrument maintenance, ultimately leading to higher sample throughput.

 

TECHNICAL POSTERS


Authors of odd-numbered posters will present their posters on Monday, July 15, from 11:00 a.m.-12:00 p.m., and on Tuesday, July 16, from 3:10-3:55 p.m.
Authors of even-numbered posters will present on Monday, July 15, from 3:10-3:40 p.m., and on Tuesday, July 16, from 11:00 a.m.-12 p.m.

Simultaneous Determination of Alternaria Toxins, Ergot Alkaloid Epimers, and Other Major Mycotoxins in Various Food Matrices by LC-MS/MS

P-36
Melinda Urich (presenter), Diego Lopez
Restek Corporation

Abstract
Various food commodities are vulnerable to different types of fungal pathogens and could be contaminated with differential classes of mycotoxins as a result. It is ideally to implement a generic method for simultaneous determination of multi-mycotoxins in different food matrices or agricultural products. In this study, a simplified sample preparation procedure and a reliable LC-MS/MS analytical method was developed for comprehensive measurement of 37 regulated and emerging mycotoxins, including five Alternaria toxins, six major ergot alkaloids and their corresponding epimers. Four different food matrices (baby wheat cereal, peanut, tomato puree, and blended flour) were chosen for method validation to demonstrate the applicability of this analytical method to a wide range of food types. Sample extraction was performed using a formic acid-acidified 80:20 acetonitrile:water solution followed by extract dry-down and reconstitution in a 50:50 water:methanol solution for injection analysis on a Biphenyl LC column. Chromatographic analysis was performed using MS-friendly acidic mobile phases and completed with a short 11-minute cycling time for proper separation of ergot alkaloid epimers. Method accuracy and precision was evaluated by fortification of food samples at three different levels. Accurate quantification was achieved using matrix-matched calibration standards at the range of 0.4 to 400 μg/kg. The recoveries of all mycotoxins (except citrinin) in fortified samples were from 70% to 120%, and the relative standard deviation was less than 20%. The established workflow was simple and fast for multi-mycotoxin determination with a unique benefit of simultaneous analysis of Alternaria toxins and ergot alkaloids. Furthermore, a novel inert Biphenyl LC column demonstrated the high degree of Non-Specific Binding (NSB) that occurs between the column’s stainless-steel hardware and certain mycotoxins. The implementation of the inert column offers a robust and improved chromatographic performance as it mitigates the NSB for highly adsorptive analytes (e.g. Fumonisins, Aflatoxins, and Tenuazonic acid) leading to better sensitivity and peak shapes without the need of mobile phase additives or sample passivation.
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Method Development for PFAS Analysis Using a Virtual Method Development Tool

P-37
Melinda Urich1(presenter), Jamie York1, Justin Steimling1, Chris Nelson1, Tim Yosca1, John Garrett2
1. Restek Corporation, 2. Analytical Innovations

Abstract
Development and optimization of liquid chromatography (LC) separations can be time-consuming and costly, often requiring many steps, including literature research, column selection, method scouting, development, and optimization. To mitigate instrument downtime for the method development process, reduce costs, and save time, an instrument-free software modeling tool was developed. This free software allows users to select compounds from a database and instantly model separations by adjusting parameters, such as instruments/system effects (dwell and extra column volume); temperature; and mobile phase additives. To deliver a fast, no-cost starting point. The current PFAS library contains 57 PFAS compounds and three bile acids, encompassing most analytes for major methods. This work demonstrates how selected methods were virtually developed and transferred to an LC-MS/MS. To determine the software’s ability to model separations, acceptance criteria was chosen based on a retention time window of ±15 seconds, selected to represent half a typical MRM window. Results show this virtual tool can be used to develop PFAS methods quickly and accurately with an improved turnaround time, optimize existing methods for the addition of new PFAS compounds, offer an on-demand consultative user experience, and greener solutions for method development.
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